Radiation was clearly emerging from the tube when the cathode rays
were streaming, and was penetrating matter to some extent.
Hertz, the discoverer of radio waves (see 1888), had found that cathode rays
could pass through thin sheets of metal, and this seemed to favor their being a wave form.
By now Perrin's work had convinced everyone that cathode rays
consisted of negatively charged particles (see 1895).
There was some question about the nature of the cathode rays
to which Goldstein had given a name (see 1876).
Today, most monitors are cathode ray
tube (CRT) devices that employ the same technology as your television.